垂直电性源瞬变电磁场时空分布特征研究

Characterization of Spatial and Temporal Distribution of Transient Electromagnetic Fields from Vertical Electric Sources

井地电磁法由于具有独特的优势在地质勘探中得到了比较广泛的应用。目前讨论比较广泛的是频率域井地电磁法,随着浅层油气已被开发以及非常规地层等诸多条件的不断限制,人们在频率域井地电磁的基础上又提出了井地瞬变电磁方法,该方法广泛应用于矿产资源勘探、水文调查、未爆物探测等领域,通过处理涡旋电磁衰减产生的二次电磁场信息来反演地层信息,其具有对高阻屏蔽弱,以及对异常体垂向分辨率高的优点。但是井地瞬变电磁在理论讨论方面还是比较少的,特别是对电性源瞬变电磁场的时空分布特征的研究,这里最难攻克的是对所运用的方法正确性、有效性的检验。故而在验证所执行程序的正确性的基础上讨论井地瞬变电磁的时空分布特点,重点研究电磁场分量E x的场值随时间的扩散特征。

Well electromagnetic method has been widely used in geological exploration due to its unique advantages.Currently more widely discussed frequency domain well ground electromagnetic method,with the shallow oil and gas has been developed as well as unconventional strata and many other conditions continue to limit,people in the frequency domain well ground electromagnetic on the basis of well ground transient electromagnetic method is proposed,the method is widely used in mineral resources exploration,hydrological surveys,unexploded ordnance detection,etc.,through the processing of vortex electromagnetic attenuation of the secondary electromagnetic field information generated by the inversion of the stratigraphic information.It has the advantage of weak shielding against high resistance,as well as high vertical resolution of anomalies.However,the theoretical discussion of well transient electromagnetic is still relatively small,especially the study of the spatial and temporal distribution characteristics of transient electromagnetic field of electrical sources,and the most difficult to overcome here is the test of the correctness and validity of the method used.Therefore,this paper discusses the characteristics of the spatial and temporal distribution of the transient electromagnetic field in ground wells on the basis of verifying the correctness of the executed program,focusing on the characteristics of the diffusion of the field values of the electromagnetic field components with time.